What is the most likely electron configuration for a 23 electron element?
1s2 2s2 2p6 3s2 3p6 3d3 4s2. The 4s electrons will be filled first because they are lower in energy, and the stability of the half-filled 3 d sub-shell means that this configuration is preferred.
This question concerns the -COOH substituent of organic acids. What is the effect of an electron withdrawing group on the strength of the acid?
An electron withdrawing group stabilizes the anion that forms, making the anion the most likely structure. This means that the proton is more likely to be donated and therefore increases the strength of the acid.
If you fill a glass to the brim with water and ice, and then the ice melts, what will happen?
The water level will drop slightly. One interesting property of water is that ice is less dense than liquid water. This means that when it melts, the density increases and therefore lowers the level of the water.